Cinnabar is a mercury sulfide mineral with the chemical formula HgS. It is a vibrant red color and is an important ore of mercury. It is primarily found as fillings within gaps of rocks and coating rocks as a result of ascending hydrothermal activity. While cinnabar is typically massive in habit, large crystals have been found on rare occasions. The striking red color of cinnabar made for an attractive pigment, however the usage of cinnabar as a pigment was halted following discovery of its toxic properties.

Toxicity Warning: The mercury content of cinnabar can be harmful if absorbed into the blood stream by inhalation or ingestion. The crystals won't pose a health hazard just sitting on a shelf but it is highly recommended that you wear gloves or wash your hands after handling.